Female Dog’s Heat Cycle

When the dogs reach sexual maturity (puberty), they will get their first estrous (reproductive or heat) cycle. Depending on the dog and breed, puberty can start as early as six months of age. Usually, dogs get estrus twice a year but this may also vary as larger breeds get once a year while smaller breeds may get even four times a year. Meanwhile, male dogs (unneutered) are sexually active all through the year.

Most dogs get to their heat about every five to seven months or about twice per year, while the gap can vary for each dog, between breeds. Toy or smaller breed dogs may cycle 3 to 4 times every 12 months, while large breed dogs may cycle only once a year. The two cycles also differ in the length of heat, hormonal changes, and discharge amount. It is normal for the young dog’s cycles to be rather erratic in the beginning stages.

For a female dog to get into a good rhythm of cycles, it can take up to two years. Domesticated dog's breeding season has no particular time of the year except for Tibetan Mastiffs and Basenji which typically have a tendency to cycle in the spring.

A typical heat period for a dog with bleeding will last two to four weeks (average 21 days heat cycle). The heat cycle is classified into 4 distinct stages, each with its own behaviors and symptoms. Bloody discharge or bleeding occurs in two of the four phases.

1. Proestrus stage

• Large, red, swollen vulva
• Discharge/bleeding from the vulva (or a red/yellow/brown discharge)
• Personality changes- changes to more affectionate or becomes grumpy
• Appetite changes
• Tail tucking
• Weeing more than usual
• Increased Licking of the Vaginal Area

2. Estrus Stage

• Lightened discharge
• Flirting
• Vulva softening for penetration

3. Diestrus Stage

• Less flirting
• The gradual disappearance of vulva swelling

4. Anestrus Stage

• Resting stage
• No signs of hormonal or sexual behavior

The heat cycle is a normal phenomenon and treatment is not required. When there are additional complications, supportive therapy is provided.

• Antibiotics - cephalexin, cefpodoxime, ceftiofur, etc.
• To stop heat cycle: Megestrol acetate / Mibolerone prevents the heat cycle from starting but it cannot completely stop the cycle. (United States Food and Drug Administration).
• Intravenous fluid and electrolyte therapy to restore and maintain fluid and electrolyte levels.
• Ovariohysterectomy (spaying) is most often the treatment of choice to remove Ovaries and uterus. This surgical removal takes about a maximum of 45 minutes and has little or no risk. There will be no pain and dogs feel only a little discomfort.

• Try to avoid off-leash walks.
• Protect your dog from unnecessary pregnancy. Never let your dog out in the yard alone.
• Choosing the right amount of rest and exercise is important to keep your dog comfortable.
• Applying Menthol on the tip of her tail is a good trick to hide the scent.
• Use a Tractive GPS tracker: When the dog in heat runs away, this will be useful in finding her whereabouts.

Owners of intact female dogs cannot prevent the heat cycle. When dog is not considered for breeding, then the chances of heat cycle can be stopped through surgery.

Female Dogs. There is no breed disposition.

1. Types

Proestrus:

• This is the first stage of the dog heat cycle.
• proestrus can last for an average of 9 days. Usually, it is from 3 to 16 days.
• This stage starts with the swelling of the vulva.
• The follicles will develop and estrogen levels will peak.

Estrus:

• This is the mating phase where your female dog will be receptive to males.
• Range of 4-21 days; Average: 9 days.
• The dog seems to be urinating more frequently than normal and this is to mark spots to indicate her willingness to breed.
• Vaginal discharge slows down and may change to a watery straw color.
• Flagging (wagging the back end and holding her tail to the side).
• Lordosis reflex (arching and raising her hindquarters and vulva up for the male).

Diestrus:

• This phase occurs directly after the “in heat” stage.
• The dog’s body will either develop into a pregnancy or return to normal.
• The disappearance of vaginal discharge will disappear.
• Return of vulva to normal size.

Anestrus:

• Anestrus is an inactive or resting phase.
• There will be no signs of sexual behavior or hormonal activities.

2. Mortality There is no documented mortality due to the heat cycle.

3. Diagnosis

• Complete physical exam
• Complete blood count (CBC), blood chemistry profile
• Electrolyte panel
• Urinalysis
• Bacterial and fungal culture
• Vaginal cytology and culture

4. Prognosis

When there are no plans to breed the dog, owners can consider waiting until after the heat cycle is over to spay her. Check with the veto to find out the appropriate age to spay the pet. If heat cycle signs persist for a longer period or if there are extreme signs, your veterinarian may need to intervene but many dogs do not cross over this period without significant issues.

Contact your vet right away, if you notice any of the following:

• Large, red, swollen vulva
• Discharge/bleeding from the vulva (or a red/yellow/brown discharge)

• Commercial foods should have high-quality, natural ingredients, with no artificial additives.
• Add fiber to your pup’s diet.
• Brown rice, lukewarm (never hot) chicken soup with Low sodium or chicken breast, and cooked vegetables are perfect for the ailing pup.
• Add a couple of spoonfuls of salmon, tuna, mackerel, anchovies, or another fish product to your dog’s food.
• Meat-flavored baby food or bland food.
• Semi-moist pet food with boiled chicken.
• Increase water intake or install a pet water fountain.

Spaying will prevent the heat cycle and hormonal changes. When your dog does experience more severe symptoms, veterinary intervention can help relieve discomfort or anxiety until the condition gets cleared up naturally.